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vfs: new superblock methods to override /proc/*/mount{s,info}

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a) ->show_devname(m, mnt) - what to put into devname columns in mounts,
mountinfo and mountstats
b) ->show_path(m, mnt) - what to put into relative path column in mountinfo

Leaving those NULL gives old behaviour.  NFS switched to using those.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2011-03-16 06:59:40 -04:00
parent f8ad9c4bae
commit c7f404b40a
3 changed files with 60 additions and 9 deletions
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21
fs/namespace.c
View File

@ -978,7 +978,13 @@ static int show_vfsmnt(struct seq_file *m, void *v)
int err = 0;
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
if (mnt->mnt_sb->s_op->show_devname) {
err = mnt->mnt_sb->s_op->show_devname(m, mnt);
if (err)
goto out;
} else {
mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
}
seq_putc(m, ' ');
seq_path(m, &mnt_path, " \t\n\\");
seq_putc(m, ' ');
@ -1025,7 +1031,12 @@ static int show_mountinfo(struct seq_file *m, void *v)
seq_printf(m, "%i %i %u:%u ", mnt->mnt_id, mnt->mnt_parent->mnt_id,
MAJOR(sb->s_dev), MINOR(sb->s_dev));
if (sb->s_op->show_path)
err = sb->s_op->show_path(m, mnt);
else
seq_dentry(m, mnt->mnt_root, " \t\n\\");
if (err)
goto out;
seq_putc(m, ' ');
seq_path_root(m, &mnt_path, &root, " \t\n\\");
if (root.mnt != p->root.mnt || root.dentry != p->root.dentry) {
@ -1060,7 +1071,12 @@ static int show_mountinfo(struct seq_file *m, void *v)
seq_puts(m, " - ");
show_type(m, sb);
seq_putc(m, ' ');
if (sb->s_op->show_devname)
err = sb->s_op->show_devname(m, mnt);
else
mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
if (err)
goto out;
seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
err = show_sb_opts(m, sb);
if (err)
@ -1086,11 +1102,15 @@ static int show_vfsstat(struct seq_file *m, void *v)
int err = 0;
/* device */
if (mnt->mnt_sb->s_op->show_devname) {
err = mnt->mnt_sb->s_op->show_devname(m, mnt);
} else {
if (mnt->mnt_devname) {
seq_puts(m, "device ");
mangle(m, mnt->mnt_devname);
} else
seq_puts(m, "no device");
}
/* mount point */
seq_puts(m, " mounted on ");
@ -1104,6 +1124,7 @@ static int show_vfsstat(struct seq_file *m, void *v)
/* optional statistics */
if (mnt->mnt_sb->s_op->show_stats) {
seq_putc(m, ' ');
if (!err)
err = mnt->mnt_sb->s_op->show_stats(m, mnt);
}

28
fs/nfs/super.c
View File

@ -263,6 +263,8 @@ static match_table_t nfs_local_lock_tokens = {
static void nfs_umount_begin(struct super_block *);
static int nfs_statfs(struct dentry *, struct kstatfs *);
static int nfs_show_options(struct seq_file *, struct vfsmount *);
static int nfs_show_devname(struct seq_file *, struct vfsmount *);
static int nfs_show_path(struct seq_file *, struct vfsmount *);
static int nfs_show_stats(struct seq_file *, struct vfsmount *);
static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
@ -296,6 +298,8 @@ static const struct super_operations nfs_sops = {
.evict_inode = nfs_evict_inode,
.umount_begin = nfs_umount_begin,
.show_options = nfs_show_options,
.show_devname = nfs_show_devname,
.show_path = nfs_show_path,
.show_stats = nfs_show_stats,
.remount_fs = nfs_remount,
};
@ -366,6 +370,8 @@ static const struct super_operations nfs4_sops = {
.evict_inode = nfs4_evict_inode,
.umount_begin = nfs_umount_begin,
.show_options = nfs_show_options,
.show_devname = nfs_show_devname,
.show_path = nfs_show_path,
.show_stats = nfs_show_stats,
.remount_fs = nfs_remount,
};
@ -726,6 +732,28 @@ static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
return 0;
}
static int nfs_show_devname(struct seq_file *m, struct vfsmount *mnt)
{
char *page = (char *) __get_free_page(GFP_KERNEL);
char *devname, *dummy;
int err = 0;
if (!page)
return -ENOMEM;
devname = nfs_path(&dummy, mnt->mnt_root, page, PAGE_SIZE);
if (IS_ERR(devname))
err = PTR_ERR(devname);
else
seq_escape(m, devname, " \t\n\\");
free_page((unsigned long)page);
return err;
}
static int nfs_show_path(struct seq_file *m, struct vfsmount *mnt)
{
seq_puts(m, "/");
return 0;
}
/*
* Present statistical information for this VFS mountpoint
*/

2
include/linux/fs.h
View File

@ -1632,6 +1632,8 @@ struct super_operations {
void (*umount_begin) (struct super_block *);
int (*show_options)(struct seq_file *, struct vfsmount *);
int (*show_devname)(struct seq_file *, struct vfsmount *);
int (*show_path)(struct seq_file *, struct vfsmount *);
int (*show_stats)(struct seq_file *, struct vfsmount *);
#ifdef CONFIG_QUOTA
ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);